---
title: "Improving Lambda Custom Runtime Cold Start and Deployment Speeds with .NET 6"
url: https://daily.dev/posts/improving-lambda-custom-runtime-cold-start-and-deployment-speeds-with-net-6-2wd1iddjb
source_url: https://nodogmablog.bryanhogan.net/2021/12/improving-lambda-custom-runtime-cold-start-and-deployment-speed-with-net-6
type: article
source: "No Dogma Blog (Bryan Hogan)"
published: 2026-05-31T07:47:06.468Z
updated: 2026-05-31T08:50:24.965Z
tags: [".net", "aws-lambda"]
reading_time: 2
upvotes: 0
comments: 0
language: en
---

> ## Documentation Index
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# Improving Lambda Custom Runtime Cold Start and Deployment Speeds with .NET 6

**[No Dogma Blog \(Bryan Hogan\)](https://daily.dev/sources/bryanhogan)** · 2 min read · 0 upvotes · 0 comments

## Summary

Two .NET 6 features — PublishTrimmed and ReadyToRun — can significantly improve AWS Lambda custom runtime cold start times and deployment speeds. Enabling PublishTrimmed in the .csproj file reduced one example deployment package from 31.4 MB to 14.4 MB, with roughly 30% cold start improvement. ReadyToRun performs ahead-of-time compilation to reduce startup delays, though it increases package size. Both features are most impactful when using a custom runtime rather than a managed Lambda runtime.

## Full article

daily.dev links to this article rather than hosting it. Read it at the original source: <https://nodogmablog.bryanhogan.net/2021/12/improving-lambda-custom-runtime-cold-start-and-deployment-speed-with-net-6>

---

Tags: [#.net](https://daily.dev/tags/.net), [#aws-lambda](https://daily.dev/tags/aws-lambda)

[View this post on daily.dev](https://daily.dev/posts/improving-lambda-custom-runtime-cold-start-and-deployment-speeds-with-net-6-2wd1iddjb)